JPS61268506A - Spike pin for tire - Google Patents

Abstract

PURPOSE:To lessen the damage of a road surface by providing an axial hole in a shank and fitting the shaft part of a supporting flange which is provided via a buffering layer, into the lower side of a shank flange. CONSTITUTION:A shank axial hole 8 having a triangular section as cut parallel with a shank flange 1, is provided in the axial direction on a shank 2, from the shank end 2a on the flange 1 side. A supporting flange 5 is provided under the shank flange 1 via an annular buffering layer 4 of a rubber elastic body, with its shaft part 7 being slidably inserted in the axial hole 8 of the shank 1 through the buffering layer 4. A space 9 is formed between the inner end 7a of the shaft 7 and the hole bottom 8a of the axial hole 8, to provide a buffering function. By this construction, a road surface contact pressure can be reduced, lessening the damage on a road surface.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to improvements in spike pins used in pneumatic tires for use on icy and snowy roads. Reduce contact pressure,
This is designed to reduce road damage.

(Prior Art) Traditionally, spike pins have a shank, usually made of steel, a tip made of a hard material, particularly a cemented carbide such as tungsten carbide, fixed to one end of the shank, and a flange provided at the other end of the shank. The spike bin is used by being embedded in the tire tread by driving it into a pin hole provided in the tire tread from the flange side of the shank, and the spike bin itself usually does not have any buffering function.

These conventional spike pins are embedded in the tire tread and have a structure that essentially uses the rubber elasticity of the tire tread itself to absorb human force, but they usually do not generate large amounts of dust when driving the spike pins. Immediately below,
Because the highly rigid belt and breakers are embedded in the rubber layer of the tread, extremely high surface pressure is applied to the tips of the spike pins. As a result, although they are effective in preventing slippage on snow, especially on icy roads, they seriously damage snow removal or ice removal roads, and as spike pins become more widespread, they have caused many social problems.

Many studies have been carried out to improve this, for example,
Attempts have also been made to use shape memory alloys to create a spike effect, in which the spike pins become shorter when the temperature is high, but become longer when the temperature drops below a certain level. However, shape memory alloys are not only fairly expensive materials, but also have problems with fatigue.
At the current stage, it is difficult to say that it can sufficiently withstand repeated human effort of about 5 to 10 million times, so it is difficult to take immediate action.

In addition to this, a spike pin with a structure in which a spring is inserted under the tip to reduce damage to the road surface on normal roads has been proposed, but when the tip is retracted, sand grains enter the gap. However, it is not put into practical use because there are problems such as the tip not being able to return to its original shape, or the sand grains abrading the space between the tip and the shank, causing the tip to come off.

Recently, Japanese Patent Application Publication No. 59-199307 and Japanese Patent Application Publication No. 5
As disclosed in Japanese Patent No. 9-199308, it has been proposed to cover the flange with a rubber material having a glass transition temperature whose hardness changes depending on temperature.

This technology basically has a conventional structure under the flange of the spike pin, which has normal rubber elasticity at temperatures above 30℃ and
Below, a buffer layer is provided which can behave as a relatively hard plastic.

However, according to this technology, the surface pressure of the tip of the spike pin on a normal road surface decreases by only about 10 to 15%, and this level is not sufficient to prevent damage to the road surface caused by the spike pin. Moreover, there is a problem in that the buffer layer receives the high impact force when the spike pin comes into contact with the road surface when the road surface becomes hard at low temperatures and becomes brittle.

Furthermore, since the depth of pin holes that can be formed in the tread rubber layer for attaching spike pins is limited, when providing a buffer layer below the flange as described above, the height of the spike pins, That is, the height from the tip end of the shank to the flange end is inevitably shortened. Therefore, when sudden braking is applied on ice, a large moment is generated with a single point on the shank near the tread surface as a fulcrum due to the extremely large shearing force applied to the spike pin tip, because the distance from the fulcrum to the flange is small. However, there is a problem in that the flanges cannot generate sufficient resistance against the above-mentioned moments, and the spike pins tilt with respect to the vertical axis, increasing the braking distance.

(Problems to be Solved by the Invention) The present invention provides a spike pin that can effectively produce a spike effect in a timely manner and can advantageously realize appropriate suppression of road surface damage caused by spikes over the service life of a tire. The purpose is to

According to the results of repeated research by the present inventor, the following important points have been determined: (1) The surface pressure applied to the tip of the currently used spike pin, approximately 173, is sufficient to provide the necessary spike effect on icy roads. You can expect it.

(2) To reduce road damage caused by spike pins,
The most effective method is to reduce the surface pressure applied to the chip.

(3) When the elastic modulus of the spike pin in the shear direction decreases, the spike effect on ice decreases.

(4) Even if rubber, which has a relatively low modulus of elasticity at room temperature, is used as a buffer layer, the rubber generally has a high Poisson's ratio and hardly changes in volume under compression, and the buffer layer does not allow the impact of spike pins. Since the bottom of the hole is surrounded by a rigid tread rubber with a belt or breaker embedded in it, there is virtually no displacement under the load acting on the spike pin, creating an effective buffering function for the spike pin. I don't get it.

(5) Rubber that has a glass transition point within the tire usage temperature range tends to creep under repeated stress at room temperature.
Furthermore, since brittle fracture is likely to occur below the freezing temperature range, there is also the problem of poor fatigue resistance and durability.

(6) The hardness of the elastic body installed under the flange of the shank of the spike pin in order to push back the spike pin that has been drawn into the tire tread in contact with the road surface is JIS hardness (
Type A) must be 15 or higher.

(Means for Solving the Problems) Taking all the above-mentioned findings into account, the inventors of the present invention have determined that the modulus of elasticity in the vertical direction can be reduced as much as possible by providing a support flange on the underside of the shank flange with a buffer layer interposed therebetween. We were able to provide a tire spike pin that maintains a modulus of elasticity in the shear direction higher than that of conventional spike pins, thereby causing less damage to the road surface and having excellent spike effects on ice.

Therefore, according to the present invention, as shown in FIG. A support flange 5 is provided on the lower side of the shank 2 via the annular buffer layer 4, and a shaft portion 7 having a cross-sectional area smaller than the cross-sectional area of the center hole 6 of the annular buffer layer 4 is installed on the support flange 5, on the flange side of the shank 2. An axial hole 8 opening at the end 2a is provided, and the support flange shaft portion 7 is slidably inserted into the axial hole 8 of the shank 2 through the center hole 6 of the annular buffer layer 4. 8 and the shaft end 7a of the support flange shaft portion 7 and the shank axial hole 8
A space 9 is provided between the dust 8a and the large dust 8a.

In addition, the support flange shaft portion is slidably inserted into the shank axial hole to allow elastic deformation of the annular buffer layer in the axial direction without relative rotation of the shank and the support flange around the axis. that the annular buffer layer has a volume of 35 to 90% of the space between the shank flange and the support flange under no-load conditions of the spike pin; and that the diameter of the flange portion of the support flange is equal to diameter, the cross-sectional shape of the shank axial hole cut parallel to the shank flange is polygonal, preferably triangular, and the cross-sectional shape of the shaft portion of the support flange is approximately the same as the cross-sectional shape of the shank axial hole. that the shank of the support flange under no load of the spike pin is at least 1. The height of the space between the inner end of the support flange shaft and the water bottom of the shank's axial hole must be within the annular buffer layer when the spike pin is under no load. The hardness of the annular buffer layer must be at least 0.5 times the height, and the hardness of the annular buffer layer is JIS hardness (Type A).
The glass transition temperature of the rubber that is the main component of the annular buffer layer is 140°C or less, and the hardness of the annular buffer layer (JIS hardness type 2A) is higher than the hardness of the tire tread. The glass transition temperature of the rubber, which is the main component of the annular buffer layer, is 10 points or more lower than 110 to +4.
It is preferred that the temperature is 0° C. and that the annular buffer layer is made of a water-containing polymer containing 150% or more of water.

(Function) The tire spike pin according to the present invention reduces the elastic modulus of the entire spike pin in the vertical direction by the action of the annular cushioning material inserted between the shank flange and the support flange, so that the elastic modulus is uniform in the axial direction. The support flange has a buffering effect and can reduce road damage, and the support flange has sufficient resistance against the moment with the shank part near the tire tread surface as a fulcrum, which is generated by shear force acting on the chip. It can be held perpendicular to the tread surface to create the desired spike effect on the ice. Therefore, on an icy and snowy road surface, the chip digs into the ice and snow to prevent slipping, and on the other hand, on a road surface without ice and snow, it is possible to reduce the surface pressure applied to the chip and prevent damage to the road surface.

In addition, the annular buffer layer has a volume of 35 to 90% of the space between the shank flange and the support flange when the spike pin is under no load, so that the buffer layer is made of an incompressible rubber elastic material. Even if the buffer layer is 35% or less, sufficient space is provided for deformation without volume change, so a sufficient buffering effect can be expected; Easily fatigued <, 90
% or more, a sufficient buffering effect cannot be expected.

However, if the buffer layer is made of foam material,
Although the +J Fuchs rubber component itself can be said to be essentially an incompressible material, since the gas in the cells has the property of being compressible, the buffer layer as a whole behaves like a compressible material. Therefore, only in this case no space is required.

By preferably making the diameter of the flange portion of the support flange larger than the flange diameter of the shank, deterioration in the function of the buffer layer can be prevented. therefore,
The shank flange is preferably smaller than the flange portion of the support flange, but the shank flange is necessary, and without it not only will it be impossible to apply force to the buffer layer, but the tire equipped with this spike pin will When rotating at high speed, there is a risk that the shank may come off due to centrifugal force.

In addition, the cross-sectional shape of the shank axial hole cut parallel to the seventh flange of the shank is polygonal, preferably triangular, and is approximately the same as the cross-sectional shape of the shaft of the support flange. The triangular shape is the most reliable because it can prevent relative rotation and the wear durability of the interface is considered. If the cross-section of the shank axial hole cut parallel to the flange is circular, relative rotation between the shank and the support flange is possible, and the shearing force applied to the tip is not applied to the center of the tip, allowing the spike pin to If a moment of rotation about the axis is generated, the buffer layer is likely to be twisted and destroyed. It has been confirmed that in the spike pins currently in use, the spike pins rotate around their axis under normal usage conditions.

Further, it is preferable that the shaft portion of the support flange enters the shank axial direction hole by at least 1.5 mm when the spike pin is under no load, and this is preferably 1.5 mm or more.
This is because if the spike pin does not go in further than this, the shank and the support flange will not act as one against the moment generated due to the shearing force applied to the tip using a certain part of the spike pin shank near the tread surface as a fulcrum.

(During industrial manufacturing, the variation in the gauge of the buffer layer becomes quite large, so a thickness of about 1.5 mm is required.If you can always produce the product as designed,
About 1.0 mm is sufficient. ) Furthermore, under the no-load condition of the spike pin, the height of the space between the inner end of the support flange shaft part in the axial hole of the shank and the large dust in the shank axial hole is preferably the height of the buffer layer. By making the buffer layer 0.5 times or more, when a vertical load is applied to the spike pin, the buffer layer deforms and softens its effectiveness against the load, making it possible to sufficiently prevent road surface damage.

The hardness of the buffer layer is preferably JIS hardness (Type A) 20~
60 provides sufficient restoring force to return the shank to its original position when the load on the spike pin is removed. If this hardness is lower than 20, the restoring force will be insufficient, and if it exceeds 60, the cushioning effect will not be expected to be significant.

The glass transition temperature of the rubber, which is the main component of the buffer layer, is 14
By keeping the temperature below 0°C, the required fatigue resistance can be ensured. If the glass transition temperature of the rubber exceeds 140°C, the temperature dependence of the elastic modulus of the material for the buffer layer will be too large, resulting in insufficient fatigue resistance. In addition, the hardness of the buffer layer (JIS hardness: A
A sufficient cushioning effect can be obtained by making the hardness of the tire tread preferably at least 10 points lower than the tire tread hardness.

In addition, by setting the glass transition temperature of the rubber, which is the main component of the buffer layer, to -10 to +40°C, it behaves relatively hard like plastic at low temperatures where a spike effect is required, but behaves like rubber at room temperature. You can make it happen. The same effect can be obtained by using a water-containing polymer containing 150% or more of water in the buffer layer.

(Example) The present invention will be explained in more detail below with reference to Examples.

[Example 1] In Example 1, in order to confirm that the spike pin according to the present invention has a low elastic modulus in the vertical direction and has an excellent spike effect on ice, the spike pin according to the present invention shown in FIG. The performance of the spike pin of Example 1 and a commercially available spike pin according to Comparative Example 1 without a buffer layer was compared.

The spike pin of Example 1 shown in FIG. 1 has a tungsten carbide tip 3 fixedly attached to a steel shank 2 in which a flange 1 is integrally formed.

The shank 2 is provided with a shank axial hole 8 having a triangular cross-sectional shape cut parallel to the shank flange 1 and extending in the axial direction of the shank 2 from the flange side shank end 2a. A support flange 5 made of steel is provided via an annular buffer layer 4 made of an elastic material. This support flange 5 is provided with a shaft portion 7 that projects upward from its upper surface, and the cross-sectional shape of this shaft portion 7 also has the same triangular shape as the shank axial hole 8. The annular buffer layer 4 made of a rubber elastic body inserted between the shank flange 1 and the support flange 5 has a volume occupation ratio of 67.9% between the flanges.
The center hole 6 has a cross-sectional area larger than the cross-sectional area of the support flange shaft portion 7. The shaft portion 7 of the support flange 5- passes through the center hole 6 of the annular buffer layer 4, and its upper end portion is slidably fitted into the shank axially large 8.
A space 9 is provided between the inner end 7a of the shank and the large dust 8a of the shank axial hole 8.

Rubber compounds as shown in Table 1 were prepared as an annular buffer layer interposed between the shank flange 1 and the support flange 5 of the spike pin.

Table 1 Nibsill VN3: Nippon Silkani Industry Co., Ltd. The spike pins of Example 1 and Comparative Example 1 were driven into a snow radial tire 187/70SR13 so that the protrusion amount was 1.5, and the tips of the spike pins were driven vertically and horizontally. The elastic modulus and spike effect on ice were evaluated when a force was applied, and the results are shown in Table 2.

〔Test method〕

(1) Vertical modulus of elasticity With only the tread part of the above test tire placed so that the spike pins are approximately in the center, a steel plate with a thickness of 1 cm was placed under the sample cut into 5 cm square pieces, and adhesive was applied. After fixing the spike pin, a load was applied to the tip of the spike pin, and the load required to distort the spike pin by 1.2 mm was evaluated.

(2) For the sample prepared with the horizontal elastic modulus (1), apply a load in the horizontal direction to the tip of the spike pin. Evaluation was made using the load required to distort the sample by 0 mm.

The evaluations for both (1) and (2) are shown in Table 2 as an index.
A larger value indicates a higher elastic modulus.

(3) Effect of spikes on ice - Spike tires made with spikes for 10k on ice at 5℃
Evaluation was made based on the force required to pull a locked tire in m/hr. This evaluation is shown in Table 2 as an index, with a larger value indicating a higher spike effect.

(Internal pressure: 1.7 kg/cr1. Static load: JIS6
0% load) Table 2 As is clear from Table 2, in Example 1, the elastic modulus in the vertical direction is significantly reduced, and therefore road surface damage is reduced.

[Examples 2 and 3] Examples 2 and 3 relate to a preferable range of the proportion of the buffer buffer layer 4 occupying the space of the shank flange 1 and the support flange 5 under an unloaded state of the spike. Table 3 shows the evaluation results for Comparative Examples 1 to 3 and Comparative Examples 1 to 3. From this, it has been found that it is preferable that the ratio be 35 to 90%.

The cross-sectional area of the spike pins of Example 2.3 and Comparative Example 2.3 was controlled by varying the inner diameter and outer diameter of the annular buffer layer of the spike pin shown in Example 1.

[Examples 4 to 7] Examples 4 to 7 relate to the evaluation of the cross-sectional shape of the shank axial hole cut parallel to the shank flange and the cross-sectional shape of the support flange shaft, and the results of the evaluation are shown in Table 4. is displayed. It has been found from this table that the cross-sectional shape is polygonal, preferably triangular, and is preferably substantially the same as the cross-sectional shape of the shank of the support flange.

In Example 5, the cross-sectional shapes of the shank axial hole and the support flange shaft portion were square as shown in FIGS. 5 to 8.

In Examples 4 to 6, the interface between the buffer layer and the flange was fixed with an adhesive, but in Example 7, no adhesive was used and the interface was left free.

From the above results, it is clear that it is better for the cross-sectional shape to be non-circular, but if it is circular, relative rotation will occur between the shank flange and the support flange, and the wrinkling will increase the strength and elasticity. This is because the rubber is concentrated in the buffer layer, which has a low efficiency, and rubber destruction occurs.

Therefore, Example 7, in which the buffer layer and the flange were not subjected to adhesive treatment, was in a better situation than Example 6. Among the systems with a circular cross-sectional shape, although not listed in the table above, the best was the system in which the buffer layer and one flange were adhesively treated, and the other was not adhesively treated.

In conclusion, any cross-sectional shape may be used as long as it prevents relative rotation between the shank and the support flange, for example, an elliptical shape may be used. Moreover, the cross-sectional shapes of the shank axial hole and the support flange shaft do not need to be the same, as long as relative rotation between the shank and the support flange can be prevented.

[Examples 8 to 13] Examples 8 to 13 relate to the hardness of the buffer layer, and from these examples, the hardness of the buffer layer is JIS hardness (A
It has been found that a value of 20 to 60 is preferable, and a value of 10 points or more lower than that of the tire tread rubber is preferable.

In this example, a spike pin having the shape shown in Example 5 was used, and a rubber composition shown in Table 5 was prepared and used as the rubber material for the buffer layer, and the evaluation results are shown in Table 6. .

(Effects of the Invention) According to the present invention, it is possible to improve the anti-slip function of a spiked tire on an icy road surface, and to significantly reduce damage to a road surface free of ice and snow.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a part of the spike pin according to the first embodiment of the present invention in longitudinal section, FIG. 2 is a plan view of the spike pin shown in FIG. 1, and FIG. Figure 4 is a cross-sectional view taken along line I in the direction of the arrow; Figure 4 is a cross-sectional view taken along line rV-rV in Figure 1 and viewed in the direction of the arrow; Figure 5 is a book with macaroni-type chips. Second invention
FIG. 6 is a plan view of the spike pin shown in FIG. 5, and FIG. 7 is a cross-sectional view taken along the line ■-■ in FIG. 5 in the direction of the arrow. FIG. 8 is a cross-sectional view taken along the line ■-■ in FIG. 5 in the direction of the arrow. 1...Shank flange 2...Shank 3...Tip 4...Annular buffer layer 5...Support flange 6...Center hole
7... Support 7 Lunge shaft end... Shank axial hole 9... Space Fig. 1 Fig. 2° Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8

Claims (1)

[Claims] 1. In a tire spike pin having a shank at one end and a tip at the other end, the shank is provided with a shank axial hole extending in the axial direction from the flange side end, and the shank A support flange is provided on the lower side of the shank via an annular buffer layer, and a support flange shaft portion provided on the support flange passes through a center hole of the annular buffer layer, and an upper end portion of the shaft portion is inserted into the axial hole of the shank. A tire spike pin characterized by being slidably inserted. 2. The support flange shaft portion is fitted into the shank axial hole so as to be slidable in the axial direction so that the shank and the support flange do not rotate relative to each other around the axis. The tire spike pin described in Scope 1. 3. The annular buffer layer covers 35% of the space between the shank flange and the support flange under the no-load condition of the spike pin.
The tire spike pin according to claim 1, characterized in that the spike pin has a volume of 90%. 4. The tire spike pin according to claim 1, wherein the diameter of the flange portion of the support flange is larger than the diameter of the shank flange. 5. The cross-sectional shape of the shank axial hole cut parallel to the shank flange is polygonal, preferably triangular, and the cross-sectional shape of the shaft portion of the support flange is approximately the same as the cross-sectional shape of the shank axial hole. A spike pin for a tire according to claim 1, characterized in that they are the same. 6. The tire spike pin according to claim 1, wherein the shaft portion of the support flange penetrates into the axial hole of the shank by at least 1.5 mm when the spike pin is under no load. 7. The height of the space in the axial hole of the shank is 0.5 times or more the height of the annular buffer layer under no-load condition of the spike pin, according to claim 1. Spike pin for tires. 8. The hardness of the annular buffer layer is 20 in JIS hardness (Type A).
The spike pin for a tire according to claim 1, characterized in that the spike pin has a diameter of 60 to 60. 9. The tire spike pin according to claim 1, wherein the glass transition temperature of the rubber that is the main component of the annular buffer layer is -40°C or lower. 10. The tire spike pin according to claim 1, wherein the hardness (JIS hardness: type A) of the annular buffer layer is 10 points or more lower than the hardness of the tire tread. 11. The tire spike pin according to claim 1, wherein the glass transition temperature of the rubber that is the main component of the annular buffer layer is -10 to +40°C. 12. The tire spike pin according to claim 1, wherein the annular buffer layer is made of a hydrous polymer containing 150% or more of water.